Spectrum access system

ABSTRACT

A method for dynamically managing spectrum access and supporting multiple tiers of users is provided. A spectrum access server receives a request from a device to access a segment of spectrum, and determines which tier of the multiple tiers is associated with the request. If the request is from a second tier user and the request does not interfere with first tier users, the request is granted. If the request is from a third tier user and the request does not interfere with first tier users and authorized second tier users, the request is granted.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional application61/766,507, filed on Feb. 19, 2013. The contents of the aboveapplication are incorporated herein by reference in their entirety.

TECHNICAL FIELD

This disclosure generally relates to spectrum access systems.

BACKGROUND

The Federal Communications Commission (FCC) regulates the use of radiofrequency bands of the electromagnetic spectrum by a spectrum managementprocess called frequency allocation. The FCC's Table of FrequencyAllocations consists of the International Table of Frequency Allocationsand the United States Table of Frequency Allocations. The FCC is alsoresponsible for managing and licensing the electromagnetic spectrum forcommercial users and for non-commercial users including: state, countyand local governments. This includes public safety, commercial andnon-commercial fixed and mobile wireless services, broadcast televisionand radio, satellite and other services.

Government agencies may have been granted use of certain spectrum. Onemethod for obtaining the spectrum for commercial use is to move theincumbent government users out of the spectrum (perhaps to a differentfrequency band) and then license the spectrum for commercial use.

SUMMARY

In general, in one aspect, a method for dynamically managing spectrumaccess and supporting multiple tiers of users is provided. The methodincludes: at a spectrum access server, receiving a request from a deviceto access a segment of spectrum; determining which tier of the multipletiers is associated with the request; if the request is from a secondtier user and the request does not interfere with first tier users,granting the request; and if the request is from a third tier user andthe request does not interfere with first tier users and authorizedsecond tier users, granting the request.

In general, in another aspect, a method for dynamic spectrum access isprovided. The method includes at a spectrum access server, receiving arequest from a first device to access a segment of spectrum; initiallygranting the first device access to the segment of spectrum at a firstmaximum allowable power level; receiving information about spectrumusage local to the first device; and dynamically adjusting the maximumallowable power level for the first device based on the informationabout spectrum usage local to the first device.

In general, in another aspect, a system for dynamically managingspectrum access and supporting multiple tiers of users is provided. Thesystem includes a first database storing information on spectrum usageof first tier users; a second database storing information on spectrumusage of second tier users; and a spectrum analytic engine to makedynamic spectrum allocation decisions based on the information in thefirst and second databases. The spectrum analytic engine is configuredto, upon receiving a request from a device to access a segment ofspectrum, determine which tier of the multiple tiers is associated withthe request, and if the request is from a second tier user and therequest does not interfere with first tier users, grant the request. Ifthe request is from a third tier user and the request does not interferewith first tier users and authorized second tier users, grant therequest.

The details of one or more implementations of spectrum access systemsare set forth in the accompanying drawings and the description below.Other features, aspects, and advantages will become apparent from thedescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an exemplary spectrum access system.

FIG. 2 is a diagram of various layers of the spectrum access system.

FIG. 3 is a diagram of components of a spectrum access manager.

FIG. 4 is a flow diagram of a process for dynamically managing spectrumaccess and supporting multiple tiers of users.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

Overview of Spectrum Access System

This disclosure describes a novel spectrum access system for allowingdynamic access of spectrum by various entities to efficiently usewireless spectrum. The system supports leaving the incumbent users inplace while also enabling new entrants to use the spectrum. The spectrumaccess system combines database information on spectrum availabilitywith sensing technology in which devices sense the surrounding spectrumto provide information about real time local spectrum usage. Bycombining timely local information with global database information onspectrum usage, the spectrum access system can support a more efficient,dynamic wireless communication system.

An advantage of the spectrum access system is that it enables incumbentspectrum users to stay in place, while other entities use the samespectrum dynamically as allowed. This enables tremendous amounts ofspectrum to be used efficiently by eliminating the time consuming andcostly step of relocating incumbent users to a new band before newoperations can begin in the band.

For example, the spectrum access system can be used to manage the use ofthe 3550-3650 MHz band, but is not limited to this frequency band.

In some implementations, the spectrum access system supports three tiersof users. Tier 1 users are the incumbent users, e.g., federal governmentagencies, such as military agencies or emergency management agencies.Tier 2 users can be, e.g., priority access users who have licenses forspectrum use as secondary users. Tier 3 users can be, e.g., generallyauthorized access (GAA) uses who do not have dedicated licenses andrequest spectrum usage from time to time on a need basis. The tier 1government agency users may have been granted exclusive use of a segmentof spectrum, but uses the segment of spectrum only in certaingeographical regions at certain times. The tier 2 and tier 3 users canbe new entrant commercial users who wish to use the same segment ofspectrum when not in use by the incumbent government agencies.

By allowing the federal incumbent users in place, the spectrum accesssystem allows freeing up a significant amount of spectrum rapidly byavoiding the time and cost associated with the conventional spectrumclearing approach. Furthermore, the three-tier model brings the benefitsof the dedicated licensed model and the unlicensed model to the marketplace for the benefit of consumers.

In some examples, the tier 1 incumbents have a guaranteed access to thespectrum and the highest priority, the tier 2 users can operate withinlimitations under the tier 1 users, and the tier 3 users can share thespectrum as long as it does not cause unacceptable interference to thetier 1 and tier 2 users.

In this description, depending on context, the term “user” may refer toa device. For example, in a spectrum access system that has multipledevices communicating with a spectrum access manager, the term “user”can refer to, e.g., base stations, mobile phones, personal computers,etc.

The spectrum access system is an active and dynamic system. The spectrumaccess system handles issues related to access control, dynamic devicemanagement, and protection of sensitive Department of Defense data. Thespectrum access system places some requirements on the end user devices,in particular related to certificate management and authentication. Thespectrum access system is responsible for implementing protocols andautomated procedures for dynamic access to spectrum.

Referring to FIG. 1, in some implementations, a spectrum access system100 manages shared spectrum and enables commercial users to share thespectrum with the incumbents. The spectrum access system 100 includes aspectrum access manager 102 and secure trusted agents on devices thatuse the shared spectrum. The spectrum access manager 102 includes one ormore databases that have information about global usage of the spectrum.The spectrum access manager can be implemented as a database or big dataanalytics system. The devices that use the shared spectrum can include,e.g., infrastructure devices 110 (e.g., base stations and WiFi accesspoints), wireless client devices 112 a to 112 c (e.g., mobile phones, orpersonal computers such as desktop, notebook, or tablet computers),machine-to-machine (M2M) system, and point-to-point communicationssystems.

For example, the one or more databases in the spectrum access manager102 can include TV whitespace databases operated by Microsoft, Google,and other entities.

In some examples, the spectrum access system 100 includes a securedatabase 104 for storing sensitive spectrum usage data. The spectrumaccess manager 102 accesses the database through a secure link 106. Byusing a separate database 104, access to the sensitive spectrum usagedata can be limited. For example, the Department of Defense may limitaccess to data regarding the location and times of operation of certainsystems. The spectrum access manager 102 can query the Department ofDefense database through a secure channel when there are requests forspecific locations and frequencies. The Department of Defense databasecan respond with the specific information for the relevant accessrequest, without making all of the data accessible to the public all ofthe time. Furthermore, the Department of Defense can limit access if itsuspects the spectrum access systems may have been compromised. Thisapproach provides a good balance between Department of Defense's concernat releasing a large amount of sensitive information to a variety ofpublic and private institutions and the need to access specificinformation to enable spectrum sharing when there are actual systemsthat need access to the spectrum.

The devices communicate with the spectrum access manager 102 through anetwork, such as the Internet 108. When a device needs access tospectrum, the device sends a request to the spectrum access manager 102,and the spectrum access manager 102 determines whether to grant accessbased on global spectrum usage information in the database 104 and localspectrum usage information provided by devices and sensors. The requestcan include information such as location, frequency bands the device canutilize, requested bandwidth, desired timeframe for operation, antennatype, antenna height above ground, and/or desired output power.

These devices that use the shared spectrum each has a security andauthentication mechanism, such as a certificate based module, tocommunicate securely with the spectrum access manager 102. The spectrumaccess manager 102 issues an authorization to each of the devices to usea certain amount of spectrum at a certain place for a certain amount oftime. An example of such an authorization is a certificate. Thecertificate has a time limitation (referred to as “time-to-live” or TTL)that can be used as a mechanism to revoke device permissions by notrenewing the authority. Device permission may fail to be renewed formany reasons, including (i) spectrum access was requested by a higherpriority user, or (ii) the device has been determined to be faulty, andno further usage authority will be granted until the flaw is verifiablyfixed.

For example, the spectrum access system 100 can enable differentlicensing regimes to coexist simultaneously, such as allowinglicense-by-rule for indoor use and other types of licenses for outdooruse.

The spectrum access manager 102 allows the incumbent spectrum users tocontinue using the spectrum and allows one or more tiers of commercialusers with different access rights and priorities. There is no limit tothe number of different tiers that can be supported. The followingdescribes as an example a three-tiered system that allows for theincumbents, priority access users, and generally authorized users (whichis similar to conventional unlicensed devices).

The spectrum access manager 102 has information regarding incumbentspectrum use and recent measurements for devices and sensors that thespectrum access manager 102 has access to. The spectrum access manager102 receives requests from devices for spectrum and makes allocationdecisions based on all of the available information.

The spectrum access manager 102 enables wireless devices to gain accessto shared spectrum as they need it. The device that wishes to gainaccess to shared spectrum first contacts the spectrum access manager102. This can be done through an existing wireless connection, such asWiFi or cellular connection, or through a wired connection. The initialauthorization of a device may occur through a wired connection, such asconnecting the device to a universal serial bus (USB) port on anInternet-connected computer. Once the device has access to sharedspectrum, future contact with the spectrum access manager 102 can bethrough this shared spectrum connection, for as long as that connectionis authorized.

The device sends an access request to the spectrum access manager 102,in which the request includes information that allows the spectrumaccess manager 102 to authenticate the device. The request includesinformation regarding the device's location, frequency bands andbandwidths that the device is capable of using, and the desired durationfor which the spectrum is requested. Based on the information that thespectrum access manager 102 has regarding incumbent users, otherauthorized commercial users, and any sensing information in the localarea that the device is requesting access, the spectrum access managerresponds with a secure authorization, for example a certificate, whichallows the device to utilize a certain spectrum band, or bands, in ageographic region for a specified period of time. The certificate mayalso specify the allowed bandwidth, transmit power limit, and anout-of-band emissions mask requirement.

The time frame authorized may or may not correspond to the requestedtime frame. The time frame, expressed as a time-to-live (TTL), servesmultiple purposes. The device can make another request as thetime-to-live time is about to expire, to continue operation. In additionto allowing the device to operate, the time-to-live parameter also setsan upper bound on how long it would take to shut down the shared usersin given areas if needed, for example, if the spectrum is needed byfirst responders in an emergency. The time-to-live parameter provides amechanism to shut down faulty devices. If a manufacturing error isdetected in a device, then future authorizations of that device type canbe denied until the flaw is remedied, and the time-to-live parametersets an upper bound on how long until all such devices are shut down.

There are several reasons why the spectrum access manager 102 may denyan access request. A request may be denied, e.g., when there is a flawin the device or when the user is inside an exclusion zone where therequested frequencies are not available. The request may also be deniedwhen there are too many devices already in operation in that region forthat spectrum, and the aggregate emissions from these devices wouldcause interference to the incumbent users if an additional device wereallowed to start operation.

The spectrum access system 100 allows for new licensing regimes that arenot possible without dynamic management of the spectrum. Dynamic devicemanagement can be made more effective by using sensing data in thedevice management algorithms. By incorporating sensing technology thatis already utilized in cellular and WiFi networks, the spectrum accesssystem 100 can manage spectrum very effectively.

Currently, many devices perform some sort of spectrum sensing. Forexample, many cellular phones periodically provide measurement reportsback to the network operator, the reports containing the identities andstrengths of the cell towers within range of the phone. Many femtocelldevices have downlink scanning capability built in, and many WiFi accesspoints have scanning capability, which is the mechanism that the WiFiaccess points use to find a channel to operate on. Requiring devices inthis band to periodically sense the spectrum and report that data backto the spectrum access system 100 will likely not increase device costbecause this capability already exists in the device and is already usedfor effective network and spectrum management in conventional networks(e.g., cellular networks). The sensing data provides timely localinformation. The spectrum access system 100 has global informationbeyond what any particular device is able to sense. The combination ofglobal and local spectrum usage information enables an efficientspectrum management scheme. The reporting of sensing data can beimplemented using the reporting mechanism already existent inconventional cellular networks, or incorporate newer technologies suchas those being developed in Defense Advanced Research Projects Agency's(DARPA's) Advanced RF Mapping program.

The devices determine their locations using, e.g., global positioningsystem (GPS) or other position locations technology. The locationsensing may not be very accurate, e.g., when the device is operatingindoors. A “trust but verify” approach can be used for determining thelocations of devices operating indoors or in other areas where preciseposition information is not easily available. The “trust” portion of theapproach can be implemented using a method similar to what has beenemployed for E911 calls over voice-over-Internet-protocol (VoIP)services. In this approach, the spectrum access manager 102 initiallyrelies upon the user or service provider to provide a location where thedevice is operating. The spectrum access manager 102 then uses availablesensing data to “verify” this information. The approximate location canbe verified using the measurement reports coming to the spectrum accessmanager from the devices in operation. If the reports show signal energyfrom a device in an area that is far away from the listed location, thenthe spectrum access manager 102 can revoke the device permissions sinceit can positively determine that the device is not in the locationlisted. The primary mechanism for this data can be, e.g., outdoordevices that have GPS capability, in which the measurement reportincludes both a known position and signal strength. Once devices areverified as being in the listed locations, their sensing data can beused to verify other devices in the vicinity.

Spectrum Access Control

Access control is an important function of the spectrum access system100. Devices need to contact the spectrum access manager 102 forpermission to use the spectrum. In order to properly implement accesscontrol, a certificate mechanism is supported by the devices. Whenpermission is granted to a device, the permission is associated with atime-to-live (TTL) parameter, requiring the device to re-authenticatewithin the time-to-live period. This provides a mechanism to effectivelyrevoke permissions from devices found to be operating out of specifiedparameters and also provides a way of temporarily “clearing spectrum” bynot renewing certificates in the case of an event that might invokepriority rights for mission critical users. The appropriate value forthe time-to-live is likely to vary with time and location, and can beset by the operator of the spectrum access system in consultation withthe federal incumbent users to balance the need between quickly clearingmalfunctioning devices and not overwhelming the spectrum access system100 with frequent renewal requests.

Permission for a device to operate may be denied by the spectrum accessmanager 102 for any number of reasons, including: the device is insideof an exclusion zone, the device has been determined to have a flaw andcannot be authorized (or re-authorized) until it is fixed by themanufacturer; or there are too many devices in operation in a particulararea which may lead to harmful interference to the incumbent. By denyingpermission when there are too many devices in operation, use of thespectrum by the incumbent can be protected. For example, in the WiFibands, there is a concern that too many users may enter into a givenarea and raise the interference floor to a level where none of thedevices can use the spectrum. In general this has not happened in theWiFi bands primarily because there is a shared interest on everyone'spart to make the spectrum useful. Individuals become their own bandmanagers and make decisions to purchase devices such as phone and awireless network hub that operate in different bands. In addition,technology advances such multiple-input-multiple-output (MIMO) haveimproved the robustness to interference of WiFi routers, allowing manymore to coexist in the same space. Future technology advances mayfurther improve the interference tolerance of these systems. Thisapproach does not work for incumbent spectrum users. Technology advancesand individual management techniques may allow generally authorizedaccess devices to be able to operate in increasing levels ofinterference over time, but the incumbent systems, such as radars, areupgraded on a much longer time cycle and will likely not improve theirrobustness to interference at the same rate. Without access control,more and more generally authorized access devices can be introduced intothe band, and they may work quite well, just as most WiFi devices dotoday. However, the aggregate interference created by the devices maygenerate crippling interference to the incumbent. The access controlmechanism in the spectrum access manager 102 is designed to avoid thisoutcome.

The access control mechanism can be used to generate different zones ofoperation, rather than just the exclusion zone and one zone ofoperation. One of the incumbent concerns is that consumer devices may beinterfered with or possibly even damaged by some of the high powersystems used by the incumbents. The spectrum access system 100 candefine multiples zones of operation in which different classes ofdevices can operate. For example, the default authorization for alldevices can be the existing 200 mile exclusion zone. Devices that havebeen certified for operation with higher tolerances to incumbent signalscan be authorized to operate in zones closer to the incumbent systems.For example, a series of concentric circles around the incumbent zone ofoperation can be used to define different access zones. The zones adevice can be authorized for depend upon the certification criteria thedevice has achieved. The device certification qualifies the robustnessto interference of the receiver as well as the survivability of thedevice under certain types of extreme high power signals. This does nothave to be a heavyweight or rigorous certification process, and can be aself-certification process. The self-certification process is simple andimposes a low cost on the device manufacturer. Because the spectrumaccess manager 102 has the ability to revoke permissions for devicesthat are found to not meet the stated criteria, the risk incurredthrough a self-certification process is low.

Dynamic Device Management

The spectrum access manager is involved in dynamically managing thedevice permissions. Unlike TV whitespaces, where the incumbenttelevision stations are stationary and new stations come on and off lineon a timescale of years, the spectrum landscape in the band for newwireless devices changes on a much more rapid time scale.

The permissions provided by the spectrum access manager 102 specifiesthe frequencies and power levels that the device is allowed to operateat, in addition to area of operation and time-to-live. The appropriatepower levels for the various tiers of operation can vary depending onthe environment. The spectrum access manager 102 determines theappropriate power levels dynamically so that the power level does nothave to be a fixed level for all places and all times. For example, inrural areas devices can be allowed to operate at higher power levels ifthe device density in the area is low. If more devices are added overtime, when the devices operating at the higher power level attempt torenew their certificates, their allowable power levels can be lowered.This maximizes spectrum utilization based upon requested usage. Thisimproves over the conventional static rules in which all devices have toabide by the same power level, even if there are relatively few inoperation in a given area, which is a waste of spectrum resources. Adynamic approach allows the spectrum usages to be maximized for thenumber of devices desiring to use the spectrum in a given time period,and to adapt that usage over time to best utilize the spectrum as thenumber of devices requesting permission changes. If necessary to beconsistent with the license-by-rule framework, a low power (e.g., 100mW) can be the default power level for the generally authorized accessdevices. This limit can then be raised based on coordination with thespectrum access manager 102 on a case by case basis.

Dynamic management combined with sensing provides a solution to theboundary problem in the hybrid model in which geographic area licensesare issued for public property or outdoor areas, while a license-by-ruleapproach is employed in private property or indoor areas. The spectrumaccess manager 102 sets an appropriate power level for thelicense-by-rule users in which different users may be allowed differentpower levels. The appropriate power level for an indoor user in adensely populated apartment building is different from that of a user ona corporate campus or rural area. Dynamic management combined withsensing data allows better management of the appropriate power levels.Initially, the device can be authorized with a power level based on theother requested use in the geographic area. The default can be a lowpower limit suitable for indoor urban settings, but if the device is inanother region or in an area where few systems are in use, the initialpower limit can be raised. As sensing data comes in from devices in thearea, the power level can be adjusted dynamically. For example, if thereare priority access devices in the area, and they report seeingsignificant outdoor power levels from a tier 3 generally authorizedaccess device, the spectrum access manager 102 can adjust the powerlimit of the generally authorized access device downwards. This can beachieved in one of two ways. If the generally authorized access deviceis connected to the network, the spectrum access manager 102 can send amessage to the device to adjust the allowable power level. If the deviceis not connected to the network, then the power level is adjusted whenthe device's time-to-live expires and the device contacts the spectrumaccess manager 102 for a new certificate. The timeframe required forsuch adjustments are a factor that should be considered when initiallysetting the length of the device's time-to-live parameter. Once thedevice has been in operation for a while, and the power levels seemsuitable, the time-to-live can be increased when the next certificate isissued to the device.

Dynamic device management through the spectrum access system 100 canmaximize spectrum utilization as the spectrum landscape changes overtime and provides an effective mechanism to manage the boundary problemin the hybrid model in which geographic area licenses are issued forpublic property or outdoor areas, while a license-by-rule approach isemployed in private property or indoor areas.

Device Requirements

In order for the spectrum access system 100 to function properly, thespectrum access manager 102 needs to trust that the devices operating inthe band will operate within the limits placed on them by the spectrumaccess manager 102. First, the spectrum access manager 102 authenticatesthe device and establishes a secure communications channel with thedevice. Second, the device is configured to operate with the limitsspecified by the spectrum access manager 102, in which the spectrumaccess manager 102 may change the limits based on time and location.

Referring to FIG. 2, each device (e.g., 110 and 112 a to 112 c) thataccesses the shared spectrum has an authentication mechanism and aresource control mechanism that only allows access to certainfrequencies if authentication has been granted for that spectrum at thatplace and at that time by the spectrum access manager 102. In someimplementations, a device 120 includes a layer 122 for securecommunication and authentication with the spectrum access manager 102,and a layer 124 for trusted access management. The layer 124 isresponsible for enforcing the limits of operation in terms of frequency,bandwidth, power, time and out of band emissions that are specified bythe certificates issues by the spectrum access system 100. Verificationof layer 124's ability to properly enforce these limits is a criticalcomponent of the device certification. The device 120 includes awireless module 126, which is the component that performs the typicalcommunication functions, such as data encoding and decoding, signalmodulation, power management, according to communications protocols.

Technical solutions for authentication and establishing a secure channelexist today in systems and standards such as X.509. See Internet X.509Public Key Infrastructure Certificate and CRL Profile, RFC 2459,http://www.ietf.org/rfc/rfc2459.txt. These are used in a wide range ofwireless systems today ranging from WiMAX radios to Android devices andsome software defined radio-based amateur radio systems. The technologyfor authenticating and securely communicating with a device is mature,cost effective and available today.

Insuring the radio operates within the limits specified by the spectrumaccess manager 102 is verified as part of the device approval process.The information provided by the spectrum access manager 102 includesallowable power levels, frequency ranges, geographic areas and atime-to-live parameter. The device has a secure mechanism that does notallow the radio to operate out of bounds in any of these dimensions. Thedevice is designed with a mechanism to limit operation in each of theparameters specified by the spectrum access manager 102, which can beimplemented in the device's firmware and tested and verified. A lightweight self-certification process can be adopted for devices, such asself-verification or a declaration of conformity so as not to increasetime to markets or place a significant cost burden on the devicemanufacturer. The spectrum access manager 102 can revoke deviceoperating permission if an issue is discovered, mitigating the need fora more formal certification process involving third parties.

FIG. 3 is a diagram showing an example of various components of thespectrum access system 100. An incumbent spectrum user data warehouse130 is provided. This is where the information regarding incumbentusers' (e.g., government agencies') spectrum usage is stored. Thisincludes frequency bands, locations of operation, time windows ofoperation if applicable, power levels, antenna heights and antenna typewhere appropriate. Note that some of the uses may be systems such asradar, for which antenna height may not be a relevant parameter. Thedata warehouse 130 stores upper and lower bounds on what acceptabletime-to-live values are for shared users. Information in this databasecan be updated often, for example, spectrum used by ships can be updatedwhen ships approach or leave ports.

A secure sensitive incumbent spectrum data warehouse 132 is provided.This is similar to the data warehouse 130, except for storing sensitivespectrum use information, for example, Department of Defense spectrumuse information, or spectrum use information for FBI surveillance.

A secure query monitor 134 monitors and possibly restricts queries tothe sensitive data warehouse 132. The secure query monitor 134 is designto protect against information mining of the sensitive information. Forexample, the monitor 134 may block sequences of queries designed togather all the database information in a short period of time.

An authorized tiered user database 136 stores the lists of identities ofusers authorized for certain tiers of usage. For example, a company maypay to have the tier 1 rights, which gives the company priority accessover everyone else except the incumbent.

A sensing data warehouse 138 collects and stores sensing data, fromdevices and independent sensors. Entries are tagged with location andtime, and stored so that operations can be performed looking at pastspectrum usage in order to predict future potential usage windows andinterference.

A certificate manager 140 authenticates devices and issues certificatesto devices to use certain spectrum in certain areas over a certain timeperiod.

A device registry 142 stores certifications of shared spectrum devices.The certifications may be self-certificates issued by the manufacturerof the devices that describe basic device capabilities. The registry 142also contains information on flaws that have been detected in order todeny operation to flawed devices until remedied.

An activity log 144 lists all spectrum certificates issued.

A visualization interface 146 allows a visual interface to spectrumusage at any time, current or a snapshot of the past (hence theconnection 158 to the activity log 144).

A secure device communication channel 148 establishes a secure linkbetween a device (e.g., 152) making a request and a spectrum analyticengine (e.g., 150).

A spectrum analytic engine 150 is the brains, accesses all of theinformation stored and executes the algorithms to make spectrumallocation decisions. For example, upon receiving a request from adevice to access a segment of spectrum, the spectrum analytic engine 150determines whether the request is from a second tier user (e.g.,priority access user) or a third their user (e.g., generally authorizedaccess user). If the request is from a second tier user and the requestdoes not interfere with the first tier users (e.g., incumbent users),the request is granted. If the request is from a third tier user and therequest does not interfere with first tier users and authorized secondtier users, the request is granted.

Note that in this description, when we say that the request from thesecond tier user does not interfere with the first tier users, we meanthat if the request is granted and the second tier user uses the segmentof spectrum as requested, it will likely not cause unacceptableinterference with the first tier users. In most cases second tier userswill be granted access at times or in places where the first tierincumbent users are not operating. When the second tier user uses thesame spectrum as that used by the first tier users at the same time,there will likely be some interference, but as long as the interferenceis negligible or acceptable to the first tier users, the request can begranted (assuming other necessary criteria are also satisfied).

Similarly, when we say that the request from the third tier user doesnot interfere with the first tier users and authorized second tierusers, we mean that if the request is granted and the third tier useruses the segment of spectrum as requested, it will likely not causeunacceptable interference with the first tier users or authorized secondtier users. When the third tier user uses the same spectrum as that usedby the first tier users and authorized second tier users at the sametime, there will likely be some interference, but as long as theinterference is negligible or acceptable to the first tier users andauthorized second tier users, the request can be granted (assuming othernecessary criteria are also satisfied).

Spectrum sharing devices 152 sends requests to the spectrum analyticengine 150 to request access to spectrum, and uses the spectrumaccording to limits specified by the certificates issued by thecertificate manager 140. There can be many devices 152 sharing thespectrum. The figure shows only one representative device. The devices152 may connect to the secure device communication channel 148 throughthe Internet 156.

A user interface 154 connects to all components to allow a user toconfigure the components and obtain status of the components. The userinterface 154 can be run remotely.

In some implementations, the spectrum access manager 102 may include theincumbent spectrum user data warehouse 130, the authorized tiered userdatabase 136, the sensing data warehouse 138, the certificate manager140, the device registry 142, the activity log 144, and thevisualization interface 146.

Referring to FIG. 4, a process 160 for dynamically managing spectrumaccess and supporting multiple tiers of users is provided. The process160 includes: at a spectrum access server, receiving a request from adevice to access a segment of spectrum (162) and determining which tierof the multiple tiers is associated with the request (164). For example,the spectrum access server can be the spectrum access manager 102 ofFIG. 1. The device can be one of the devices 110 or 112 a-112 c of FIG.1.

If the request is from a second tier user and the request does notinterfere with first tier users (166), the request is granted (168). Ifthe request is from a third tier user and the request does not interferewith first tier users and authorized second tier users (170), therequest is granted (168). If the request interferes with the first tierusers or authorized second tier users, the request is denied (172). Forexample, the first tier users can include incumbent users, the secondtier users can include priority access users, and the third tier userscan include generally authorized access users.

The spectrum access manager 102 can include one or more processors andone or more computer-readable mediums (e.g., RAM, ROM, SDRAM, hard disk,optical disk, and flash memory). The one or more processors can performvarious operations described above. The operations can also beimplemented using application-specific integrated circuits (ASICs). Theterm “computer-readable medium” refers to a medium that participates inproviding instructions to a processor for execution, including withoutlimitation, non-volatile media (e.g., optical or magnetic disks), andvolatile media (e.g., memory) and transmission media. Transmission mediaincludes, without limitation, coaxial cables, copper wire and fiberoptics.

The features described above can be implemented advantageously in one ormore computer programs that are executable on a programmable systemincluding at least one programmable processor coupled to receive dataand instructions from, and to transmit data and instructions to, a datastorage system, at least one input device, and at least one outputdevice. A computer program is a set of instructions that can be used,directly or indirectly, in a computer to perform a certain activity orbring about a certain result. A computer program can be written in anyform of programming language (e.g., C, Java), including compiled orinterpreted languages, and it can be deployed in any form, including asa stand-alone program or as a module, component, subroutine, abrowser-based web application, or other unit suitable for use in acomputing environment.

Suitable processors for the execution of a program of instructionsinclude, e.g., both general and special purpose microprocessors, digitalsignal processors, and the sole processor or one of multiple processorsor cores, of any kind of computer. Generally, a processor will receiveinstructions and data from a read-only memory or a random access memoryor both. The essential elements of a computer are a processor forexecuting instructions and one or more memories for storing instructionsand data. Generally, a computer will also include, or be operativelycoupled to communicate with, one or more mass storage devices forstoring data files; such devices include magnetic disks, such asinternal hard disks and removable disks; magneto-optical disks; andoptical disks. Storage devices suitable for tangibly embodying computerprogram instructions and data include all forms of non-volatile memory,including by way of example semiconductor memory devices, such as EPROM,EEPROM, and flash memory devices; magnetic disks such as internal harddisks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROMdisks. The processor and the memory can be supplemented by, orincorporated in, ASICs (application-specific integrated circuits).

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinventions or of what may be claimed, but rather as descriptions offeatures specific to particular embodiments of particular inventions.Certain features that are described in this specification in the contextof separate embodiments can also be implemented in combination in asingle embodiment. Conversely, various features that are described inthe context of a single embodiment can also be implemented in multipleembodiments separately or in any suitable subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the embodiments described above should not be understoodas requiring such separation in all embodiments, and it should beunderstood that the described program components and systems cangenerally be integrated together in a single software product orpackaged into multiple software products.

Thus, particular embodiments of the subject matter have been described.Other embodiments are within the scope of the following claims. In somecases, the actions recited in the claims can be performed in a differentorder and still achieve desirable results. In addition, the processesdepicted in the accompanying figures do not necessarily require theparticular order shown, or sequential order, to achieve desirableresults. In certain implementations, multitasking and parallelprocessing may be advantageous.

A number of implementations of the invention have been described.Nevertheless, it will be understood that various modifications can bemade without departing from the spirit and scope of the invention. Forexample, the spectrum access manager 102 may include a billing modulethat supports a mechanism in which users can pay for access, and thefees may vary according to tier level. The spectrum access system 100may support more than three tiers of users. There can be multiplespectrum access systems, and the operators of the spectrum accesssystems may coordinate to share basic spectrum usage information. Theremay be a synchronization interface to enable one spectrum access systemto synchronize with other spectrum access systems. The synchronizationinterface may connect to the analytics engine and the certificatemanager. Every time a certificate is issued, the synchronizationinterface uses a verification process (similar to that used in amulti-user database) to make sure that the other spectrum access systemsdo not issue conflicting certificates at the same time.

Accordingly, other embodiments are within the scope of the followingclaims.

What is claimed is:
 1. A method for dynamically managing spectrum accessand supporting multiple tiers of users, the method comprising: at aspectrum access server, receiving a request from a device to access asegment of spectrum; determining which tier of the multiple tiers isassociated with the request; if the request is from a second tier userand the request does not interfere with first tier users, granting therequest; and if the request is from a third tier user and the requestdoes not interfere with first tier users and authorized second tierusers, granting the request.
 2. The method of claim 1, comprising if therequest is from a second tier user and is likely to cause interferencewith the first tier users, denying the request or replying with amodified grant that differs from the original request and is compatiblewith spectrum usage by first tier users.
 3. The method of claim 1,comprising if the request is from a third tier user and is likely tocause interference with the first tier users or authorized second tierusers, denying the request.
 4. The method of claim 1, comprising if therequest is from a third tier user, determining a number of third tierusers in an area in which the third tier user that sent the request islocated, determining whether aggregate interference from the third tierusers in the area is likely to cause unacceptable interference to thefirst tier users or authorized second tier users, and denying therequest if the aggregate interference is likely to cause unacceptableinterference to the first tier users or the authorized second tierusers.
 5. The method of claim 1 in which the first tier users compriseincumbent users, the second tier users comprise priority access users,and the third tier users comprise generally authorized access users. 6.The method of claim 1, comprising collecting real time spectrum usageinformation from at least one of sensors, second tier users, or thirdtier users, and determining whether the request from the second tieruser will interfere with the first tier users based on the real timespectrum usage information.
 7. The method of claim 1, comprisingcollecting real time spectrum usage information from at least one ofsensors, second tier users, or third tier users, and determining whetherthe request from the third tier user will interfere with the first tierusers or authorized second tier users based on the real time spectrumusage information.
 8. The method of claim 1 in which granting therequest to a second or third tier user comprises issuing a certificatethat specifies a time limitation for which the second or third tier useris authorized to use the segment of spectrum.
 9. The method of claim 8in which the certificate specifies a location limitation in which thesecond or third tier user is authorized to use the segment of spectrum.10. The method of claim 8, comprising before the time limitationexpires, receiving a second request from the device to renew access tothe segment of spectrum, and determining whether to grant the secondrequest based on spectrum usage information that is collected after thefirst request is granted.
 11. A method for dynamic spectrum access, themethod comprising: at a spectrum access server, receiving a request froma first device to access a segment of spectrum; initially granting thefirst device access to the segment of spectrum at a first maximumallowable power level; receiving information about spectrum usage localto the first device; and dynamically adjusting the maximum allowablepower level for the first device based on the information about spectrumusage local to the first device.
 12. The method of claim 11 in which theinformation about spectrum usage local to the first device includesinformation on the number of devices also accessing the segment ofspectrum.
 13. The method of claim 12 in which dynamically adjusting themaximum allowable power level for the first device comprises setting themaximum allowable power level for the first device based on the numberof devices that are also accessing the segment of spectrum.
 14. Themethod of claim 13 in which dynamically adjusting the maximum allowablepower level for the first device comprises increasing the maximumallowable power level for the first device when there are fewer devicesaccessing the segment of spectrum.
 15. The method of claim 14 in whichdynamically adjusting the maximum allowable power level for the firstdevice comprises decreasing the maximum allowable power level for thefirst device when there are more devices accessing the segment ofspectrum.
 16. A system for dynamically managing spectrum access andsupporting multiple tiers of users, comprising: a first database storinginformation on spectrum usage of first tier users; a second databasestoring information on spectrum usage of second tier users; and aspectrum analytic engine to make dynamic spectrum allocation decisionsbased on the information in the first and second databases, in which thespectrum analytic engine is configured to, upon receiving a request froma device to access a segment of spectrum, determine which tier of themultiple tiers is associated with the request, if the request is from asecond tier user and the request does not interfere with first tierusers, grant the request, and if the request is from a third tier userand the request does not interfere with first tier users and authorizedsecond tier users, grant the request.
 17. The system of claim 16 inwhich the first tier users comprise incumbent users, the second tierusers comprise priority access users, and the third tier users comprisegenerally authorized access users.
 18. The system of claim 16 in whichthe first database stores information on at least one of frequency band,location of operation, time window of operation, power level, antennaheight, or antenna type of one or more incumbent users.
 19. The systemof claim 16, comprising a third database having information onidentities of users authorized to request access to the segment ofspectrum.
 20. The system of claim 16, comprising a certificate managerthat issues certificates to one or more second or third tier users touse the segment of spectrum in certain areas over certain time periods.